PNOWWA Report Summary

Summary of the context and overall objectives of the project

In Air Traffic Management (ATM) the 4D trajectory management is a necessary concept to meet future growth in air traffic. However, aircraft always deviate from the planned 4D trajectory due to uncertainties during flight, departure and arrival airport. Therefore, there is a clear need to move to probability forecasts both in the local operational user environment and en-route. This project concentrates in quantifying the uncertainties related to delays at ground operations due to winter weather situations. The overarching objectives of using probabilistic forecasts in ATM applications are to support the timely operations in surface management and ATM decision making, to increase airport capacity, as well as to shorten delays and promote safety. The PNOWWA project will provide the scientific basis for these ground-braking improvements in the 4D trajectory management.

The modern networked ATM world includes decision making and alternative plans on many levels from ground handling to deploying remote tower activities and balancing capacity between routes and airports. Automatic and semiautomatic decision making systems are deployed to ensure resilience and to optimize the use of resources. For such use, the probabilistic forecasts is the most natural way to act.

The full utilization of the probabilistic forecast needs seamless co-operation in development of the forecasting system and the ATM systems using it. Simultaneous development of SESAR2020 solutions for ATM applications enables the integration of probability forecasts from the concept level, and timing of this project allows us to raise awareness in a wide sector of aviation industry.

The improvements in the 4D trajectory management of air traffic to be provided by the PNOWWA project are of extreme importance for the European society due to ever increasing air traffic - especiallly because also the rate of increase of air traffic is predicted to be higher during the next decade. Hence the the scientific basis - provided by the PNOWWA project - enabling the quantification of the uncertainties related to delays at ground operations due to winter weather situation is of paramount importance for European air traffic.

The overall objectives of the PNOWWA project are a) to develop a method for probabilistic 0-3h forecasts (nowcasts) of snowfall and freezing rain at airport, in steps of 15 minutes, b) to improve our understanding, and hence predictability, of changes in snowfall intensity caused by underlying terrain, e.g., mountains and sea, c)Identify and promote the potential for use of probability forecasts in variety of airport activities and d) to make research demonstration of probabilistic winter weather product to show its potential for increasing the resilience of ATM system to winter weather.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

We have implemented software to calculate probabilistic nowcasts using three different methods. The scientifically most accurate method seems to take too long calculation times to be operationally feasible so work for finding an optimal combination continues. We are planning to execute the research demonstrations with a simpler method requiring acceptable amount of computational power.

Calculation of nowcasts with same methods for different areas has already revealed visible differences. We have identified periods for which analysis of historical data can be used to quantify the effects caused by underlying terrain, e.g., mountains and sea.

In the frame of the WP4 (Assessment of the potential of the ATM tools and roadmap generation) we performed a survey for determining the user needs and use of winter precipitation forecast at one selected airport. Results of the survey are under review and will be published in the beginning of the year 2017.

We have worked extensively in the planning and definition of the research demonstrations so that we could perform them in the next springtime. The current plan calls for the first of the research demonstration campaigns to be organized in January 2017. We have found cooperating partners from the ATM side to participate in the demonstration, representing different areas and different occupations. Preparations are well under way and there are no visible risks or issues preventing the campaign.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Our research work on the probabilistic nowcasting of winter weather for airports is clearly beyond the state of the art. We have adapted a novel methodology to probabilistic nowcasting of snowfall. This approach is required because of different behaviour of snowfall patterns in different spatial scales. For this reason we have also made preliminary analysis of additional advanced optical methods such as the diffusion method that uses a consistency measure between forward- and backward-computed velocity fields in order to increase robustness.

We have also done preliminary research with results beyond the state of the art - and tests with actual data - concerning the spatial varibility in the reliability of nowcasts due to sea, lake and orographic effects and how to incorporate such knowledg into our probabilistic nowcasting system.